Effects of pH, carbonate, calcium ion and humic acid concentrations, temperature, and uranium concentration on the adsorption of uranium on the CTAB-modified montmorillonite

With the aim of gathering uranium from ground aquatic environment in which uranium mainly occurs in negative species, the montmorillonite (MT) intercalated with cetyltrimethylammonium bromide (CTAB) was fabricated. X-ray diffraction and Fourier transform infrared spectroscopy were utilized to prove the entrance of CTAB into MT. Adsorption of uranium onto CTAB-MT was studied with respect to effect of pH, carbonate, calcium, humic acid, contact time, initial uranium concentration, and temperature. The adsorption negatively depended on pH, carbonate and calcium ion and humic acid concentrations. CTAB-MT had a higher uranium adsorption ability. The maximum monolayer uranium adsorption amount of CTAB-MT calculated by well fitted Langmuir model was determined as 213.31 mg g −1 , preceding 82.17 mg g −1 of MT. The adsorption kinetics was well fitted by pseudo-second-order model. The uptake mechanism involved ion exchange and electrostatic attraction. The adsorption was endothermic and spontaneous. The results demonstrated CTAB-MT was promising to separate uranium from ground water.